Apparatus for mixing finely divided solid particles and liquid



Nov. 3 1953 M. B. NlcHoLLs 2657911 APPARATUS FOR MIXING FINELY DIVIDED SOLID PARTICLES AND LIQUID Filed Aug. 3, 1949 MALCOLM B. NICHOLLS HIS ATTORNEY Patented Nov. 3, 1953 APPARATUS FOR MIXING FINELY DIVIDED SOLID PARTICLES AND LIQUID Malcolm B. Nicholls, Cincinnati, Ohio, assignor to Troy Engine and Machine Company, Troy, Pa., a corporation of Pennsylvania Y Application August `3, 1949, Serial No. 108,282

6 Claims.

This invention relates to a method ci mixing and Ia mixer for combining' finely divided solid materials with a liquid vehicle to form an intermixed mass, and it particularly pertains to mixing the components of a batch more thoroughly an intimately into a homogeneous mass and carrying out the mixing operation Without creating any objectionable amount of dust from the finely divided solid material which is being mixed with the liquid vehicle.

In mixing nely divided solid particles with a liquid vehicle, such` as in making paints, inks and like mixtures, it has been the common practice to place the finely divided solid material in a container, rotatable or stationary, and then rotate a mixing blade or blades Within the `container until the contents are ymixed together. As a result of this operation, all the solid particles in the batch. are stirred yand Iagitated throughout the mixing operation, including those which are remote from the liquid vehicle as Well as those which are next to it, so that many of the finer particles of the batch escape without being entrapped by the liquid in the mixed mass. This condition is not only objectionable because of loss of material, filling the air with the fugitive dust particles and dirtying the machinery, but it interferes with other batches being or to be mixed and affects their color so that the colors of the diiferent colored batches are difficult to control and cannot be regulated with any degree of accuracy even by ilrst carefully cleaning the machinery and Waiting for the dust to settle out of the atmosphere.

In the present invention, however, the mixing operation is mainly carried out beneath the exposed surface or at the bottom of the batch, within the container, with only minimum agitation of any of the exposed solid particles so that substantially all agitation before entrapment of the solid particles by the liquidis confined beneath the exposed surface of the batch Within the container Where the solid particles are next adjacent to the side and bottom walls of the container near the liquid and are confined against escape. Only those particles lof the solid material are agitated which are below the exposed surface, and the agitation progresses by circumferentially moving the solid material about the liquid core in which the mixer blade is stationary. This result is obtained -by first vplacing the liquid vehicle in the container beneath the finely divided solid partcles, rotating the container relatively to a non- 2 driven mixing blade, or blades, which is immersed within the batch contents until the blade, or blades, is rotated by the drag of the mixed portion of the batch, and then power driving the blade, or blades to complete the mix. As a result of this method, essentially all agitation of the 4solid particles is beneath the exposed part of the batch, and the exposed part of the solid particles in the batch is not agitated until after nearly all of the parti-cles have been entrapped in the mixture by the liquid vehicle. Then, the mixing blade, or blades, is power driven suiiiciently to counteract the pull by the mixed mass until all of the finely di- Yvided particles have been incorporated into the mixture. By this mixing operation, generation of dust is practically eliminated land the ingredients are more intimately commingled than when the mixing blade is rotating with the cony tainer at the beginning of the mixing operation.

One o-f the principal objects of my invention is to mix a batch of finely divided solid particles with a liquid vehicle Without permitting any substantial amount of the finely divided particles escaping entrapment by the liquid vehicle.

Another object of the invention is to mix a batch of finely divided solid particles with a liquid vehicle with a minimum agitation of the kexposed iinely divided particles.

Another object of the invention is to mix a batch of finely divided solid particles with 'a liquid vehicle by mixing the solid particles into the liquid progressively from the bottom to the Vvtop of the batch.

Another object of the invention is to circumferent1ally move the solid particles of a batch about the liquid with a nominally freely rotatable mixing blade projecting in the liquid.

t n container and the batch, and to power drive the blade, or blades, at the end of the mixing operation only, and then mainly to counteract the drag upon the blade, or blades, by the mixed portion of the rotating batch.

Further objects and objects relating to the details of construction and economies of operation Will definitely appear from the detailed description to follow. In one instance I have accomplished the objects of my invention by the device and means set forth in the following specication. My invention is clearly defined and pointed out in the appended claims. A structure constituting a preferred embodiment of my invention and for carrying out the method is illustrated in the accompanying drawing forming a part of this specification in which the single figure is a. cross-sectional view through the center of a machine embodying my invention.

Referring specifically to the drawings in which like numerals are used to designate like parts, there is an angular mixer having a base or bottom i with a rotatable turntable 2 rotatably mounted on one end on which a tub or container 3 may be placed. A motor I is mounted on they opposite end of the base with interposed driving mechanism between the motor and the turntable. The turntable is rotated by the motor by means of any suitable power transmission mechanism. There is a pedestal 5 provided on the base for rotatably supporting the turntable 2. An antifriotionbearing 1 is interposed between the ledge. 8 on the top of the pedestal and thebottom end of the hub member 9 which is between the top.l of the pedestal and the turntable. A driven pulley I:0 is attached tothe hub member, and is preferably provided on the periphery of its rim Il with a plurality of annular, V-shaped grooves i2, each` receiving a power transmission belt I3 which is connected to a similar groovel in shaft I6. A sealingV ring or gasket I6 is inserted between an annular groove formed in the top. of the pedestal, and thebottoml ofthe hub member for sealing a fluid within the chamber i1, surroundiing the antifriction bearing.

A jack shaft i8 is fitted in the pedestal with its upper endprojecting intothe central bore of the hub member 3 in which asleeve i9- is placed to be interposed between the hub` member and theupwardly projecting end of the jack shaft. There is a radialr bore: 20; having a grease gun fitting therein whereby a grease gun may be em'- ployed for injecting a lubricant inte the longitudnal* bore 2i inthe jack shaft which connects with a radial bore or: bores 21a leading to the bearingsurface between the sleeve andtheshaft for lubricating the bearing. The open end; of. the

lubricating duct is covered by a plate 22 that seats within a recessv 23 whichY is formed at the top of the-.hub member. The turntable seats onthe pedestal andcan be secured. thereto'4 by any suitable fastening means such as screwy 24". A1 closure plate 25 is seated within a recesstliat is formed in thebottom of; the pedestal and is held inplace by screws 2li, closing. the end: of thev boreforthe jack shaft. The invention is not limited:

table with its openend up in position to-be closed" by a lid or cover 21 which is associated with the mixer unit 28- that is adapted to be raisedl or lowered for withdrawing the mixing blade 28 from the container or projecting it therein. In

order that the operator of the machine may viewl the mixture inside the container without removf ing the lid, a slight opening is provided in said` lid having a cover place 30 hinged at one end vat 3l and having a latch 32 at its othery end. The

mixer unit is attached to a support that is pivoted to the base at 35A. The tank lid4 or cover is also attached to the support 3l and will be moved on and off the top of the container'or tub` when the mixer unit is moved to have themixing blade 29 projected inor withdrawn-from the con'- tainer or tub. The mixer unit comprises spindle 36 driven by motor 31 which is attached to the support 34, the spindle having mounted on its bottom end a substantially U-shaped blade 29 having a pair of side arms 38 and 39 which are connected, by a bottom portion 4|), to each other with the part 3l vertically disposed with its outer edge slightly spaced from the inside wall of the container or tub and the portion I0 horizontally disposed with its bottom edge slightly spaced from the bottom of the container or tub. The spindle 36 intersects the vertical axis of the container` or tub substantially coincident with or above the center point at the level of the batch of the material which is placed within the container or tub. The vertically disposed arm 38 is of a length substantially less than the height of the batch so that its top end will terminate short of be conned below the level of the batch. Accordingly, the agitation of any exposed materialv within the container or tub will be limited to that which isaroundV the spindle where it pr jects into the batch-,. and since the intersection. of the spindle and the vertical axis of the con tainer is coincident with or above the center point at the level of the batch', the exposed psrticles atr this point will not be stirred up but vm slightly, if. at all'. The spindle from` the point at and below which it contacts the batchv ingrediente is substantially coincident with the vertical axis of' the container. Th1:v spindle with the blade thereon can be driven by the motor 3`|f which is mounted on the1 support M, but it is' not driven thereby at the beginning of themixing operationV of the batch but only' after the batch or a sub stantial part thereof has beensutiiciently mixedi intol a conglomerate viscous mass suticient to cause the-spindle to rotate'wiishI it asa result of the rotationaly movement of theV mass;

The spindle can bev power` driven sufficiently' to' counteract the drag exerted upon the blade by? thek rotating mixed mass. At this" stage of the mixing operation, most ofthe solid-.particles havef been entra'pped and thel rotation. of the spindle does not agitate any great.V amount of exposed" entrapped particles;

The support'. 3K can bev turned'. about. thef pivotl 35 by. a handswheelwhichisiconnectedto suitable:

conventional worinY gearing (not shown) fbrnrov ingthesupport on and.v off:r the container.v A swg!A screwr 4U may be fittedl to me. support. in. posi'- tion tov abut against some fixed part of the' base'. when the support is-swung back to remove the` mixer from the tub or' container. A shield' can be provided between the movable support and the base t'ojlreep'tliedrivir'1g'-mechanism covered,

and this shieldm'ay comprise one part 48 movable with the support and anotherv part n fixedvv to The mixing spindle is preferably detacha connected to the-'motor driven chuck shaft' l by having its end fittedV into me4v socket le' mone end of the chuck shaft and held by aV pinA 50 which is projected through' the' spindle and the chuck'shaft. Accordingly; the mixing spindle' may be readily detached and attached to the chuck shaft;

The shaft lsisjournaied mbearmgs siiiith'eA base and has a pulley 32' keyed theretov at 53,' the periphery, of the pulley being grooved with a plurality of grooves to receive transmission belts" 54`that connects said pull'eytoA a pull'eylwhicii is on' the shaft of the motor 'li Then'xotor liis adjustably mounted upon the base and may be adjusted by screw 56 that is fitted to the angle member 51 xed to the base. The bottom end of the shaft l5 is closedby a plate 58 screwed threaded at 59 to the mounting 60 for one of the bearings.

In carrying out my invention a tub or container is placed on the turntable with a batch of ingredients placed therein. The liquid vehicle is rst placed in the tub or container, and the finely divided solid particles are placed on top of the liquid vehicle. The mixer unit is moved for the blade on the end of the spindle to be projected in the tub or container and be immersed in the batch with the cover or lid closing the top of the tub l on, but the blade on the spindle projecting into ,a

the container into the batch is not driven. Accordingly, all agitation of the batch is at the bottom of the tub or container beneath the exposed surface of the batch where all the liquid vehicle is concentrated and the solid particles are confined. By not rotating the blade at the beginning of the mixing operation, the finely divided particles are not agitated at the exposed surface of the batch, and all of them will be entrapped by the liquid vehicle without allowing any substantial quantity to escape. Furthermore, for some apparent reason more intimate mixing of the ingredients is obtained inasmuch as a batch mixed by this method needs to be run through a grinding mill for the final mixing operation only about twice rather than about four or five times as heretofore where the batch has been mixed by power driving both the blade and the tub or container simultaneously throughout the mixing operation. It is not apparent why a more intimate and better preliminary mix is obtained by my method, but one theory is that the liquid and solid particles are more closely brought into contact without violent agitation and with a more constant and uniform rubbing effect therebetween to better wet the solid particles, whereas with both the blade and the container or tub being rotated at the beginning of the mixing operation, the ingredients are too violently agitated to permit all of the individual solid particles being wetted with the liquid vehicle. Whatever may be the reason, lt is a known fact that a more intimate mixing of the ingredients is not only obtained but the mixing is effected with a minimum of agitation of the finely divided solid particles at the exposed surface of the batch until after all of them have been wetted by the liquid vehicle and entrapped in the mixed mass.

As the ingredients of the batch become well mixed into a homogeneous mixed mass while being rotated, a drag is exerted upon the blade, causing it and the spindle to be rotated, and this rotational pull is increased as the Whole batch becomes intermingled into a conglomerate viscous mass. When the freely rotatable spindle carrying the mixing blade begins to be rotated by the mixed batch in the rotating container, the spindle can then be power driven to complete the mixing operation. While the blade is being rotated by the pull of the rotating mixed mass, obviously there is less resistance or drag by then power driving the spindle than if it Was not power driven and left free. Therefore, power driving the spindle at this stage of the mixing operation continues this even uniform spread of the in' gredients and wetting of the solid particles until intermingling of the solid finely divided particles and the liquid vehicle has been substantially complete and all the solid particles are entrapped in the liquid. Power driving the mixer at this time speeds up the nal phase of the mixing operation and cooperateslas to conglomerate all the ingredients without unnecessary and objectionable agitation of the solid particles as would result by powen driving the spindle at the beginning of the mixing operation.

I am'aware that the structure shown herein and that the method described are susceptible of considerable variation without departing from the spirit of my invention and therefore I have claimed my invention broadly as indicated in the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by United States Letters Patent, is:

l. A mixing machine comprising a rotatable turntable on which a container is adapted to be rotated, power transmission means for rotating the turntable, a freely rotatable spindle mounted upon an adjustable support, an angular blade fixed to the end of the spindle in position to be moved in and out of the container by adjustment of the support, said blade having one portion disposed parallel to the sidewall of the container and slightly spaced therefrom and another portion disposed parallel to the bottom wall of the container and slightly spaced therefrom, both of said portions of the blade terminating below the surface level of a batch of materials to be mixed in the container, and a separate power transmission means for the spindle.

2. A mixing machine Ias set forth in claim l in which the spindle is angularly disposed and intersects the vertical axis of the turntable above the center of the batch level.

3. A mixing machine comprising a support on which a container is adapted to be rotated, power transmission means for rotating the container, a freely rotatable spindle mounted upon an adjustable support, an angular blade fixed to the end of the spindle in position to be moved in and out of the container by adjustment of the support, said blade having an arm portion disposed to be slightly spaced from the sidewall of the container and another arm portion disposed to be slightly spaced from the bottom wall of the container, both of said arm portions of the blade terminating below the surface level of a batch of materials to be mixed in the container, and the blade being connected to the spindle at about the vertical axis of the container, and power transmission means for rotation of the spindle at will.

4. A mixing machine as set forth in claim 3 in which the connection between the blade and the spindle, above the surface level of the batch, is substantially coincident with the vertical axis of the container.

5. A mixing machine comprising a rotatable support for a container, a container mounted upon said support, means for rotating the support with the container thereon, a spindle journaled in a support and mounted for freely rotating therein with one end in a. vertical plane common to the vertical axis of the container and projecting into the container below the surface level of a batch of materials placed within the container to be mixed, a blade fixed to the end of the spindle which projects within the contumor, and means for 'rotating at `will the inormolly ltroeiy .rotatabie spindle.

6. A mixing machine as vset forth in chum 5 in which the connection :between the blade and the-spihd1e,ais thesurfacelevel ot the batch, is substantially coincident with the verticalrxis fthecontliner.

`MALCOLJi/I vB. NICHOLLS.

lReferences Cited in the file o! this fpatent STATES PATENTS Number Number Number Name Dub Cleveland Nov. 1898 Wadsworth 0ct.'8, im

FOREIGN PATENTS Country Date France Feb. 21. i914 (1st addition to 397,129)

Germany June 23, Ii915 France Aug. 28. 1935 

